1. Field of the Invention
The present invention relates to a hydrodynamic bearing assembly.
2. Description of the Related Art
A hard disk drive (HDD), an information storage device, reads data stored on a disk or writes data to a disk using a read/write head.
The hard disk drive requires a disk drive device capable of driving the disk. In the disk drive device, a small-sized spindle motor is commonly used.
The small-sized spindle motor may use a hydrodynamic bearing assembly. A lubricating fluid is interposed between a shaft and a sleeve of the hydrodynamic bearing assembly, such that the shaft is supported by fluid pressure generated in the lubricating fluid.
At the time of initial spindle motor operation, the lubricating fluid concentrated on a dynamic pressure generation groove may have high pressure and low pressure regions along a circumference of the shaft, such that the shaft may fluctuate, thereby causing vibrations and noise.
Therefore, a method of reducing the generation of vibrations and noise at the time of initial motor operation has been demanded.